epan/dissectors/packet-dmx-chan.c

   1 /* packet-dmx-chan.c
   2  * DMX Channel Data packet disassembly.
   3  *
   4  * $Id$
   5  *
   6  * This dissector is written by
   7  *
   8  *  Erwin Rol <erwin@erwinrol.com>
   9  *  Copyright 2011 Erwin Rol
  10  *
  11  *  Wireshark - Network traffic analyzer
  12  *  Gerald Combs <gerald@wireshark.org>
  13  *  Copyright 1999 Gerald Combs
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 51 Franklin Street, Fifth Floor
  28  * Boston, MA  02110-1301, USA.
  29  */
  30
  31 /*
  32  * This dissector is based on;
  33  * American National Standard E1.11 - 2004
  34  * Entertainment Technology USITT DMX512-A
  35  * Asynchronous Serial Digital Data Transmission Standard
  36  * for Controlling Lighting Equipment and Accessories
  37  */
  38
  39 #include "config.h"
  40
  41 #include <epan/packet.h>
  42 #include <epan/wmem/wmem.h>
  43 #include <epan/prefs.h>
  44
  45 void proto_register_dmx_chan(void);
  46
  47 static int proto_dmx_chan = -1;
  48
  49 static int hf_dmx_chan_output_dmx_data = -1;
  50 static int hf_dmx_chan_output_data_filter = -1;
  51
  52 static int ett_dmx_chan = -1;
  53
  54 /*
  55  * Here are the global variables associated with the preferences for DMX
  56  */
  57 static gint global_disp_chan_val_type = 0;
  58 static gint global_disp_col_count     = 16;
  59 static gint global_disp_chan_nr_type  = 0;
  60
  61 static void
  62 dissect_dmx_chan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  63 {
  64         col_set_str(pinfo->cinfo, COL_PROTOCOL, "DMX Channels");
  65         col_clear(pinfo->cinfo, COL_INFO);
  66
  67         if (tree != NULL) {
  68                 static const char *chan_format[]   = {
  69                         "%2u%% ",
  70                         "0x%02x ",
  71                         "%3u "
  72                 };
  73                 static const char *string_format[] = {
  74                         "0x%03x: %s",
  75                         "%3u: %s"
  76                 };
  77                 wmem_strbuf_t *chan_str = wmem_strbuf_new_label(wmem_packet_scope());
  78                 proto_item    *item;
  79                 guint16        length,r,c,row_count;
  80                 guint8         v;
  81                 guint          offset   = 0;
  82
  83                 proto_tree    *ti = proto_tree_add_item(tree, proto_dmx_chan, tvb, offset, -1, ENC_NA);
  84                 proto_tree    *dmx_chan_tree = proto_item_add_subtree(ti, ett_dmx_chan);
  85
  86                 length = tvb_reported_length_remaining(tvb, offset);
  87
  88                 row_count = (length / global_disp_col_count) + ((length % global_disp_col_count) == 0 ? 0 : 1);
  89                 for (r = 0; r < row_count;r++) {
  90                         for (c = 0;(c < global_disp_col_count) && (((r * global_disp_col_count) + c) < length);c++) {
  91                                 if ((global_disp_col_count >= 2) && ((c % (global_disp_col_count / 2)) == 0)) {
  92                                         wmem_strbuf_append(chan_str, " ");
  93                                 }
  94
  95                                 v = tvb_get_guint8(tvb, (offset + (r * global_disp_col_count) + c));
  96                                 if (global_disp_chan_val_type == 0) {
  97                                         v = (v * 100) / 255;
  98                                         if (v == 100) {
  99                                                 wmem_strbuf_append(chan_str, "FL ");
 100                                         } else {
 101                                                 wmem_strbuf_append_printf(chan_str, chan_format[global_disp_chan_val_type], v);
 102                                         }
 103                                 } else {
 104                                         wmem_strbuf_append_printf(chan_str, chan_format[global_disp_chan_val_type], v);
 105                                 }
 106                         }
 107
 108                         proto_tree_add_none_format(dmx_chan_tree, hf_dmx_chan_output_dmx_data, tvb,
 109                                                         offset+(r * global_disp_col_count), c,
 110                                                         string_format[global_disp_chan_nr_type],
 111                                                         (r * global_disp_col_count) + 1, wmem_strbuf_get_str(chan_str));
 112                 }
 113
 114                 /* Add the real type hidden */
 115                 item = proto_tree_add_item(dmx_chan_tree, hf_dmx_chan_output_data_filter, tvb,
 116                                                 offset, length, ENC_NA );
 117                 PROTO_ITEM_SET_HIDDEN(item);
 118         }
 119 }
 120
 121 void
 122 proto_register_dmx_chan(void)
 123 {
 124         static hf_register_info hf[] = {
 125                 { &hf_dmx_chan_output_data_filter,
 126                         { "DMX data filter",
 127                                 "dmx_chan.data_filter",
 128                                 FT_BYTES, BASE_NONE, NULL, 0x0,
 129                                 NULL, HFILL }},
 130
 131                 { &hf_dmx_chan_output_dmx_data,
 132                         { "DMX data",
 133                                 "dmx_chan.dmx_data",
 134                                 FT_NONE, BASE_NONE, NULL, 0x0,
 135                                 NULL, HFILL }},
 136         };
 137
 138         static gint *ett[] = {
 139                 &ett_dmx_chan
 140         };
 141
 142         module_t *dmx_chan_module;
 143
 144         static const enum_val_t disp_chan_val_types[] = {
 145                 { "pro", "Percent", 0 },
 146                 { "hex", "Hexadecimal", 1 },
 147                 { "dec", "Decimal", 2 },
 148                 { NULL, NULL, 0 }
 149         };
 150
 151         static const enum_val_t disp_chan_nr_types[] = {
 152                 { "hex", "Hexadecimal", 0 },
 153                 { "dec", "Decimal", 1 },
 154                 { NULL, NULL, 0 }
 155         };
 156
 157         static const enum_val_t col_count[] = {
 158                 {  "6",  "6",  6 },
 159                 { "10", "10", 10 },
 160                 { "12", "12", 12 },
 161                 { "16", "16", 16 },
 162                 { "24", "24", 24 },
 163                 { NULL, NULL, 0 }
 164         };
 165
 166         proto_dmx_chan = proto_register_protocol("DMX Channels","DMX Channels", "dmx-chan");
 167         proto_register_field_array(proto_dmx_chan, hf, array_length(hf));
 168         proto_register_subtree_array(ett, array_length(ett));
 169         register_dissector("dmx-chan", dissect_dmx_chan, proto_dmx_chan);
 170
 171         dmx_chan_module = prefs_register_protocol(proto_dmx_chan, NULL);
 172
 173         prefs_register_enum_preference(dmx_chan_module, "dmx_disp_chan_val_type",
 174                                         "DMX Display channel value type",
 175                                         "The way DMX values are displayed",
 176                                         &global_disp_chan_val_type,
 177                                         disp_chan_val_types, FALSE);
 178
 179         prefs_register_enum_preference(dmx_chan_module, "dmx_disp_chan_nr_type",
 180                                         "DMX Display channel nr. type",
 181                                         "The way DMX channel numbers are displayed",
 182                                         &global_disp_chan_nr_type,
 183                                         disp_chan_nr_types, FALSE);
 184
 185         prefs_register_enum_preference(dmx_chan_module, "dmx_disp_col_count",
 186                                         "DMX Display Column Count",
 187                                         "The number of columns for the DMX display",
 188                                         &global_disp_col_count,
 189                                         col_count, FALSE);
 190 }
 191